meissner



N0. 623,6". Patented Apr. 25, I899. W. 0. MEISSNEB.

COMBINED LISTENING AND RINGING KEY FOR TELEPHONE SWITCHBOARDS.

(Application filed Jan. 4, 1899. (N0 Model.) 2 Sheets-Sheet I.

l l l Tum ' 4W M Jo No. 623,6". Patented Apr. 25, I899.

' w. 0. MEISSNER.

GOMBlNED LISTENING AND BINGING KEY FOR TELEPHONE SWITCHBOARDS.

(Application filed Jan. 4, 1899.) (No Model.) 2 Sheets-Sheet 2.

m: Norms PEYERS c0 PHOTGLITHO WASHINGTON. u c

UNiTnn STATES PATENT @rrrcn. I

\VILLIAM O. MEISSNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO PETER C. BURNS, OF SAME PLACE.

COMBINED LISTENING' AND RINGING KEY FOR TELEPHONE-SWITCHBOARDS.

SPECIFICATION forming part of Letters Patent No. 623,61 1, dated April 25, 1899.

Application filed January', 1899. Serial No. 701,157. (No n10del.l-

To (r66 w/wm it may concern.-

Be it known that I, WILLIAM O. Mnissnnn, a citizen of the United States of America, and a resident of Chicago, Cook county, Illinois, have invented certain new and useful Improvements in a Combined Listening and Ringing Key for Telephone-Switchboards, of which the following is a specification.

In a telephone system the lines or circuits of the various subscribers extend to a central station and terminate therein upon a telephone-switchboard. The lines or circuits of the various subscribers terminating at the switchboard are connected together in pairs for conversation upon the switchboard by means of operators. The line or circuit of each subscriber upon entering the exchange is terminated at the switchboard in a conducting-socket, and the sockets of any given pair of subscribers are connected together electrically by what are termed plugs and cords. A plug and cord consists simply of two metallic conductors with insulated handles connected together by. means of a flexible conductor. To connect together any given pair of subscribers, it is simply necessary to insert one plug of the pair in the socket or spring-jack, as it is called, of the calling subscriber and the other plug of the pair in the socket or spring-jack of the subscriber with whom connection is desired. It is evident that the subscriber must be provided with means whereby to signal the central station, and thus attract the attention of the operator. The operator must be provided with means whereby to connect her telephone with the line of the subscriber extending the call and also with means whereby to signal the subscriber with whom connection may be desired. In fact, it is essential that the operator may be able to signal either one of two connected subscribers. This result has been accomplished by means of what are termed listening and ringing keys or switches, by means of which the operator switches her telephone into the circuit between a given pair of plugs and also by means of a switch connects the cord-circuit with a source of constant-current supply. These ringing and listening keys, as heretofore, are complicated and require considerable manipulation in order to accomplish the various necessary results. In the operation of a telephone-exchange it is essential to good service that-the connections shall be promptly efliected, and in order to accomplish this result the various movements of the operator must be reduced to a minimum.

My invention relates to certain improvements in acombined listening and ringingkey of the character as hereinbefore described, and it is designed to provide means whereby the operator may switch in the telephone or ring either one of two connected subscribers through and by the instrumentality of one lever or handle.

To this end my invention consists in certain construction and circuit arrangement hereinafter to be described, reference being now had to the accompanying drawings, in whicl1' Figure 1 is a side View of my improved combined listening and ringing key. Fig. 2 is a vertical central section of the same. Fig. 3 is an edge view of the same. Fig. at is a detailed sectional view of the upper portion of my improved listening and ringing key, the full lines designating one operative position of the key-lever and the dotted lines indicating another position. Fig. 5 is a detailed perspectiveview of the under side of the supporting-plate, showing the movable shifting block. Fig. 6 is a plan view of the listening-key with the top plate partly broken away and the keylever in section. Fig. 7 is a sectional view on the line a a of Fig. 1. Fig. 8 is a diagrammatic view showing two subscribers stations connected with my improved listening and ringing key at the central station, the key being divided longitudinally and shown in two parts in order to illustrate the front and back contacts, the dotted lines indicating the position assumed by the contact-strips and keylever when extending a signal to one station and the full lines indicating the position of the parts when the subscribers lines are connected together for conversation, with the operators telephone set excluded from said circuit. Fig. 9 is a like view, the dotted lines indicating the positions assumed by the parts when a signal is being extended to the other one of thetwo subscribers stations and the full lines indicating the position assumed by the parts when the operators telephone set is included in the circuit for the purpose of conversation with either one of the two subscribers.

In carrying out my invention I provide means whereby with only one lever or handle manipulated by the operator at the centralstation switchboard the apparatus is capable of performing all the functions necessary to signal either one of two subscribers or exclude or include the operators telephone set from or in the cord-circuit, whereby to establish means for conversation between the operator and either one of the two subscribers.

I will now proceed to describe the construction of the combined listening and ringing key, as it is called, and then describe the circuit connections and its operation in connection therewith.

The apparatus or device has an insulatingplate 20, of insulating material, to which the frame 21, of ordinary construction and material, is secured. The lever 22 extends from above the plate 20 through a slot therein to a point belowsaid plate and is provided with a cam-head 23, positioned between the several contact-strips. The cam-head and lever are pivoted at 24. A contact-making block 25 is positioned within guides 26 011 the under side of the plate 20, and the lever 22 passes through a slot 27 in said contact-making block 25. By this means the lever 22 is adapted to move the block 25 laterally in two directions as said lever is moved in the arc of a circle upon its pivot 24. Arranged on either side of the cam-head 23 of the lever 22 are the several contact-strips, which I shall designate in connection with a description of the circuit ar rangement with which this combined listening and ringing key is employed. This contact-making block is adapted to engage and laterally move either one of a pair of contactstrips, which are respectively designated at 28 and 29. Thus, as shown in Fig. 4, when the lever 22 is moved into the position as shown by the dotted lines, the contact-strip 28 will be brought into contact with the contact-strip 30, and likewise when the lever is moved into the position as shown by the full lines in Fig. l the contact-strip 29 is brought into contact with the contact-strip 31.

In Figs. 8 and 9 I have shown diagrammatically the circuit connections between two telephone substations A and 13, extended to and connected at a central exchange, the switchboard being omitted for the sake of clearness. In these views I have divided the apparatus into two parts, showing the front and back contacts, respectively, separated one from the other, it being, however, understood that these strips are arranged in one unitary structure. In order to extend a signal from the central exchange to, for instance, the station 13, the operator will first insert one of a pair of plugs (designated at 32) in the spring-jack 33 of station I on the switchboard. By this means station E is connected with the plug 32, which latter is connected in turn with the contact-strip 29. The operator then moves the lever 22 into the position shown by the dotted lines in Fig. 8, thus forcing the contact-strip 2!) into contact with the strip 31, connected with the generator 35. The contact-strip 29 is forced against the contact strip 31 by the contact-making block 25, which slides along the under side of the base plate 20 when moved by the lever 22. The circuit may be traced under these conditions from the generator 35 through the lead 36 to the strip 31, from thence through the strip 29 to the lead 37,connected with the plug 32, from the plug to the contact-spring of the jack 33 through the subscribers station to the sleeve of the jack 33, through the back contact 29 to the back contact 31, and from thence over the lead 38 to the generator 35. In order to signal the station A, for instance, the opera= tor will throw the lever 22 into the position as shown by the dotted lines in Fig. 9 after having first inserted one of a pair of'plugs 32 into the spring-jack 39. As the contact between the strips 31 and 29 is now open, the current traverses the lead 36 from the generator 35 and traverses the strips and 28, which have been brought togetherin contact by the contact-making plate 25. The course of the circuit under these conditions may be traced as follows: from the generator over lead 36 to contact-strip 30, from contact-strip 28 to the plug 32, from the tip of the plug to the spring of the spring-jack 39 through the subscribers station A to the sleeve of the spring-jack, and from thence over the lead 42 to the back contacts 28 and 30 to and through the lead 38 to the generator 35. \Vhen the subscriberdesires a connection and signals the central station to this effect, the operator immediately selects one of'a pair of plugs 32 and inserts it in the spring-jack belonging to this subscriber. It then becomes necessary that the operator have means of communication with the subscriber extending the call. This is accomplished by means of a switch, or, as it is termed, a listeningkey.

As previously outlined, the primary object of my invention is to accomplish the result of signaling to either one of two subscribers or switch in the operators set in order to communicate with them by diifering movements of one lever in a convenient and natural manner. Assume that the subscriber at station A has signaled the central exchange by means not necessarily shown. The operator inserts the plug 32 in the spring-jack 39 of that subscriber and then moves the lever 22 into the position shown by the full lines in Fig. 0. The cam-head 23 forces the contactstrip 43 against the short supplemental strip 44, mounted on the contact-strip 45, thus establishing contact between the strip 43 and the strip 45 and between the back contacts 43 and 45. The course of the circuit may be traced under these conditions from the operators set (indicated generally at 46) and comprising a transmitter and receiver through the lead 47 to the contact-strip 43, from thence through the contact-strip through the contact-strip 28, the plug 32, and the springjack.39, through the subscribers station A, through the sleeve of the jack, and from thence over the lead 42, connected with the sleeve of the jack 39, to the back contactstrip 28, over the back contact-strip 45 to the back contact-strip 43, and from thence over the lead 49 to the operators set 46. Under such circuit conditions the transmitter of the operators set 46 mayinquire of the calling subscriber the number of the subscriber with whom it is desired to be connected. The calling subscriber then informs the operator of the number desired, and the operator thereupon inserts the plug of the pair in the answering-jack of that subscribers line on the switchboard and then by the means heretofore described connects the called-subscribers line with the generator in order to extend a signal to that station in a manner heretofore described. It is necessary now to remove or exclude the operators set from the connected circuit between the two subscribers, and this is accomplished by means of the lever 22, which is restored into the position shown by the full lines in Fig. 8, the circuit to the subscribers set being broken between the contact-strips 43 and 45 and the normal circuit established between the con tact-strips 28, 45, 28, and 45. The circuit under such conditions may betraced as follows: over the subscribers station A to the tip of the plug 32, from thence to the contactstrip 28, over contact-strip 45 to the contactstrip 50, over contact-strip 29, lead 37, to the tip of the plug 32, inserted in the jack 33 of station B, through said station to the sleeve of the jack 33, over the back contacts 29 and 50, the back contacts 45* and 28, through the lead 42, and to the sleeve of the jack 39 of station A.

It will be evident fromthe foregoing description that only one lever is employed, instead of either two levers or a lever and two pushbuttons, in order to ring out over the lines of either the calling or called subscriber and that the lever can be made to assume the three different positions in order to accomplish this result by easy and natural movements of the hand, remaining in whatever position it is placed and readily assuming a normal position connecting the two subscribers together when touched by the finger.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is

1. In a combined ringing and listening key, a single lever, a head thereon, and a slidingcontact-maker member operated by said lever, together with contact-strips operated by said head and sliding-contact-maker member. 2. In a combined ringing and listening key,

a single lever, a head thereon, and a slidingcontaot-maker member consisting of a movable block through which said lever passes and by which it is operated, together with contact-strips operated by said head and sliding-contact-maker member.

3. In a combined ringing and listening key, a single lever, a cam-shaped head thereon, and a sliding-contact-maker member operated by said lever, together with contact-strips operated by said cam-shaped head and slidingcontact-maker member.

Signed by me, at Chicago, county of Cook, Illinois, this 31st day of December, 1898.

' WILLIAM O. MEISSNER. WVitnesses:

CHAS. C. BULKLEY, A. MILLER BELFIELD. 

